The present invention relates to a process for producing a carbon monoxide-rich gas with a carbon monoxide contents of at least 98% by volume by means of an endothermal catalytic conversion of hydrogen with carbon dioxide.
The so-called conversion reaction EQU CO+H.sub.2 O.revreaction.CO.sub.2 +H.sub.2 -.DELTA.H
which is an equilibrium reaction results in a shifting of the equilibrium to the right at decreasing temperatures and to the left at increasing temperatures. For this purpose carbon monoxide which is present in the starting gas is reacted with steam to form carbon dioxide and hydrogen in the presence of suitable catalysts. The formed carbon dioxide can then be removed from the gas current by a washing operation. As appears the equilibrium in this case is shifted from the left to the right and the released heat of reaction is discharged by the steam which is used in the reaction in an excess.
There are, however, also situations where a carbon monoxide-rich gas is required for instance as a reduction gas or as an oxosynthesis gas. One has accordingly already attempted to make use of the conversion reaction in the reverse direction.
For instance from the French Pat. No. 1,410,951 a process is known for making oxosynthesis gas in which in a first stage natural gas is catalytically split into a hydrogen-rich gas. The latter is then further reacted with a mixture of carbon dioxide and oxygen. The amount of added oxygen is such that a catalytic combustion is maintained to the extent that it is necessary to furnish the required heat of reaction which causes the equilibrium of the conversion reaction to be shifted from the right to the left, that is, towards the side of the carbon monoxide. Thus, a complete conversion of the carbon dioxide in the second stage of the process is accomplished.
Processes are also known in which the production of carbon monoxide-rich gases is effected by the endothermal catalytic reaction of hydrogen with carbon dioxide according to the above conversion reaction. However, in these cases the starting products were always gaseous or liquid hydrocarbons which usually were first subjected to a preliminary cleavage in order to obtain a hydrogen containing gas which then was further reacted with carbon dioxide.
As distinguished from these processes, the present invention has the object to provide for a process which permits the use of fine grained and even dust-like fuels, particularly coal dust as starting material for the production of a carbon monoxide-rich gas.